Zyklon B Could Not Have Worked as Described

The chemistry of Zyklon B and human death is well established and well within the parameters of the SS operation as described. Zyklon B is hydrogen cyanide (HCN) absorbed onto a porous carrier (originally diatomaceous earth, in the form sold during the war as small pellets) for safe transport and handling, with a stabiliser added to prevent premature off-gassing. When the pellets are exposed to air at room temperature, the HCN is released as a gas; in a sealed chamber with a substantial concentration of HCN, unprotected humans die within a few minutes from cyanide-induced cellular asphyxia. The lethal concentration is well below 100 ppm for sustained exposure; a concentration of approximately 300 to 500 ppm is sufficient to kill within a few minutes. The Auschwitz gas chambers operated at concentrations of several thousand ppm during the killing phase, well above the lethal threshold. The chemistry has been examined by multiple forensic and chemical authorities since 1945 and is not in dispute outside the denier literature. The denier “engineering” reports rest on a series of methodological errors that the proper scientific literature has identified and addressed.

What Zyklon B was and how it was used

Zyklon B was developed in the 1920s by Walter Heerdt at the company Degesch (Deutsche Gesellschaft für Schädlingsbekämpfung) for industrial fumigation against insect pests, particularly in flour mills, ships and warehouses. The active ingredient was hydrogen cyanide; the carrier was originally diatomaceous earth (in the form sold during the war as small pellets), and from 1929 a chemical stabiliser was added (originally a chloroform-bromoacetate mixture) to delay off-gassing. The product was supplied in sealed metal cans of approximately 200 to 1,500 grams. The product was widely used across Europe in the 1930s for industrial pest control; the Auschwitz-Birkenau camp had a substantial pre-existing inventory of Zyklon B for de-lousing prisoner clothing and barracks against the typhus-carrying lice that were a major cause of mortality in the camps.

The SS adopted Zyklon B for the gas chamber operation at Auschwitz in summer 1941, after experiments by Karl Fritzsch (the Auschwitz deputy commandant) on Soviet POWs and selected sick prisoners. The first large-scale gassing operation at Auschwitz was conducted on 3 to 5 September 1941 in the basement of Block 11 (the camp prison), killing approximately 600 Soviet POWs and 250 sick Polish prisoners. The operation was then moved to the morgue of Crematorium I (in the main camp), to the temporary gas chambers at Bunkers I and II in Birkenau (converted farmhouses), and finally to the four large purpose-built gas chambers in Crematoria II, III, IV and V at Birkenau, operational from spring 1943. The use of Zyklon B at Auschwitz is documented in the camp’s surviving SS purchasing records (the Höss-led Schutzhaftlagerverwaltung correspondence with the Tesch und Stabenow distribution firm, captured at the war’s end), in the testimony of the Topf and Sons engineers who built the crematoria (Fritz Sander, Kurt Prüfer, Karl Schultze), in the testimony of the SS men who operated the chambers (Pery Broad, Hans Stark, Oswald Kaduk, others tried at the Frankfurt Auschwitz Trial), in the testimony of the Sonderkommando prisoners who survived (Filip Müller, Henryk Tauber, Ya’akov Gabai, Shlomo Venezia, Daniel Behnamias), and in the perpetrator memoir of camp commandant Rudolf Höss written in Polish custody before his execution.

The Leuchter Report and its problems

The principal denier “engineering” challenge is the Leuchter Report of 1988, prepared by Fred Leuchter (an American execution-equipment maintenance technician with no qualifications in chemistry, history, or forensic science) at the request of Ernst Zündel for use in his Canadian trial for spreading false news. Leuchter visited Auschwitz, took samples without permission from the walls of the surviving gas chamber structures, sent them to a Massachusetts laboratory for cyanide-residue analysis, and concluded from the results that the structures had not been used for cyanide-based gassing. The report has been examined extensively in the scholarly literature and was the subject of detailed analysis at the Irving v. Lipstadt trial in 2000 by the architectural historian Robert Jan van Pelt and the chemist Richard Green. The principal problems with the report:

The samples were taken from the surviving structures, which by 1988 had been exposed to forty-three years of weather, water infiltration, vegetation, biological activity and visitor traffic. The original wall surfaces, where the cyanide residues would have accumulated, had largely deteriorated; the bulk samples Leuchter took included substantial later concrete and masonry that had not been present during the killing operation.

The analytical method used (a bulk acid digestion of the samples, with detection of total cyanide by colorimetry) does not distinguish surface residues from bulk material; the result is dominated by the bulk material, in which little cyanide is expected even on the proper history. The proper method, as the Polish Forensic Institute (Markiewicz et al., 1994) demonstrated, is selective extraction targeting the surface stratum where cyanide salts would have been deposited. The Markiewicz analysis, using the proper method on samples from the same buildings, found cyanide residues consistent with the chambers’ history.

The comparison Leuchter drew between the residues in the killing chambers and the residues in the de-lousing chambers (where Zyklon B was used routinely against insect pests, with much higher cumulative exposure than the killing chambers received) was the wrong comparison: insects are far more resistant to cyanide than humans, requiring concentrations approximately 10 to 30 times higher and exposure times approximately 10 to 100 times longer; the de-lousing chambers therefore received vastly higher cumulative cyanide doses than the killing chambers, and would be expected to retain far higher residues even on the historical record as established. Leuchter’s finding that the killing chambers had less residue than the de-lousing chambers is therefore consistent with, not contrary to, the historical record. Van Pelt’s testimony at the Irving trial walked through this point in detail.

The Rudolf Report (Germar Rudolf, 1993) and the Lüftl Report (Walter Lüftl, 1992) are attempts to update and defend Leuchter’s analysis, with somewhat more sophistication. Both have been examined and rebutted in the scholarly literature: the Rudolf report by Richard Green and others, the Lüftl report by the Austrian forensic chemist Hans Schäfer. The methodological problems are similar to those of Leuchter; the Rudolf report adds layers of theoretical chemistry that do not address the underlying sampling and methodology problems.

The Mr Justice Gray finding

The Irving v. Lipstadt trial of 2000 examined the gas chamber chemistry in detail. Mr Justice Gray’s judgment of 11 April 2000, in section 7 of the judgment, addressed the Leuchter Report explicitly. The judgment found that “the evidence on the part of the Defendants by Professor van Pelt, taken in conjunction with that of Dr Green and others, demonstrates that no objective historian, having considered the evidence, could doubt that there were gas chambers at Auschwitz and that they were operated on a substantial scale to kill hundreds of thousands of Jews”. The judgment specifically rejected Leuchter’s methodology and conclusions. This is the most extensive judicial finding on the gas chamber chemistry; it was made after an adversarial trial in which Irving had unrestricted opportunity to present the denier case.

Why the claim is harmful

The claim is harmful because it dresses methodologically inadequate work in the vocabulary of engineering and chemistry, with the implicit suggestion that the denier “experts” have produced legitimate technical critiques of the historical record. The Leuchter, Rudolf and Lüftl reports do not survive proper scientific scrutiny; their findings have been examined by qualified forensic chemists, by architectural historians, and by adversarial legal proceedings, and have been found wanting. The denier presentation of these reports as technical authorities works on listeners who have not encountered the proper scientific literature; it does not survive contact with that literature. The claim that “the chemistry does not work” is the inverse of what the proper chemistry shows.

What is the actual chemistry of Zyklon B and human death? What did the Leuchter Report do, and what did the Markiewicz Report find? What did Mr Justice Gray’s judgment find on the chemistry?

See also

• The Leuchter Report Proved No Gas Chambers
• David Irving
• Rudolf Höss
• Soviet Prisoners of War
• The Irving versus Lipstadt Libel Trial
• Deborah Lipstadt

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Sources

• Charles Gray (Mr Justice Gray), Judgment in Irving v. Penguin Books Ltd and Deborah Lipstadt, 11 April 2000, particularly Section 7 on Auschwitz and the gas chamber evidence
• Robert Jan van Pelt, The Case for Auschwitz: Evidence from the Irving Trial, Indiana University Press, 2002
• Jan Markiewicz, Wojciech Gubała and Jerzy Łabędź, A Study of the Cyanide Compounds Content in the Walls of the Gas Chambers in the Former Auschwitz and Birkenau Concentration Camps, Institute of Forensic Research, Kraków, 1994
• Fred A. Leuchter, An Engineering Report on the Alleged Execution Gas Chambers at Auschwitz, Birkenau and Majdanek, Poland, Samisdat, 1988
• Richard J. Green, “Chemistry is Not the Science: Rudolf, Rhetoric and Reduction”, The Holocaust History Project, with detailed rebuttal of the Rudolf Report, https://phdn.org/archives/holocaust-history.org
• Jean-Claude Pressac, Auschwitz: Technique and Operation of the Gas Chambers, Beate Klarsfeld Foundation, 1989, the foundational architectural-technical study
• Jean-Claude Pressac, Les Crématoires d’Auschwitz: La machinerie du meurtre de masse, CNRS Editions, 1993
• Rudolf Höss, Commandant of Auschwitz: The Autobiography of Rudolf Höss, World Publishing, 1959, the autobiography written in Polish custody
• Filip Müller, Eyewitness Auschwitz: Three Years in the Gas Chambers, Stein and Day, 1979, the testimony of a Sonderkommando prisoner
• Pery Broad, KL Auschwitz Seen by the SS, Auschwitz-Birkenau State Museum, 1972, the testimony of an SS man at Auschwitz
• Henryk Tauber, testimony to the Polish Commission for the Investigation of Hitlerite Crimes, 24 May 1945, in Auschwitz Inmates’ Manuscripts, Auschwitz-Birkenau State Museum, 1973
• USHMM Holocaust Encyclopedia, “Auschwitz” and “Gas Chambers”, https://encyclopedia.ushmm.org